An LT (Luby Transfer) code is representative of prior art disappearance correction codes. Features of this code are that it assumes a communication path as a disappearance communication path, a transmitter side can arbitrarily code a packet having an information length k so that the packet has a code length n which falls within the limit n>k, and a receive side can succeed in decoding the information packet k only by successfully receiving at most (n+ε) (ε≈1.05 to 1.2×n) packets (for example, see nonpatent reference 1).    [Nonpatent reference 1] Michael Luby, “LT codes”, in Proceedings of ACM Symposium on FOCS, 2002.
A problem with LT codes is, however, that because a random number sequence is used in order to form an LT code, good performance is not achieved particularly for a short-length LT code. The present invention is provided in order to solve this problem, and it is therefore an object of the present invention to form a deterministic systematic LDPC code using a pseudo circulant matrix other than a random number sequence.